'\" e
'\"! eqn | mmdoc
'\"macro stdmacro
.ds Vn Version 1.2
.ds Dt 24 September 1999
.ds Re Release 1.2.1
.ds Dp Jan 14 18:30
.ds Dm 01 passthrou
.ds Xs 49492 4 passthrough.gl
.TH GLPASSTHROUGH 3G
.SH NAME
.B "glPassThrough
\- place a marker in the feedback buffer

.SH C SPECIFICATION
void \f3glPassThrough\fP(
GLfloat \fItoken\fP )
.nf
.fi

.SH PARAMETERS
.TP \w'\f2token\fP\ \ 'u 
\f2token\fP
Specifies a marker value to be placed in the feedback buffer
following a \%\f3GL_PASS_THROUGH_TOKEN\fP.
.SH DESCRIPTION
.P
Feedback is a GL render mode.
The mode is selected by calling
\%\f3glRenderMode\fP with \%\f3GL_FEEDBACK\fP.
When the GL is in feedback mode,
no pixels are produced by rasterization.
Instead,
information about primitives that would have been rasterized
is fed back to the application using the GL.
See the \%\f3glFeedbackBuffer\fP reference page for a description of the
feedback buffer and the values in it.  
.P
\%\f3glPassThrough\fP inserts a user-defined marker in the feedback buffer
when it is executed in feedback mode.  
\f2token\fP is returned as if it were a primitive;
it is indicated with its own unique identifying value:
\%\f3GL_PASS_THROUGH_TOKEN\fP.
The order of \%\f3glPassThrough\fP commands with respect to the specification
of graphics primitives is maintained.  
.SH NOTES
\%\f3glPassThrough\fP is ignored if the GL is not in feedback mode.
.SH ERRORS
\%\f3GL_INVALID_OPERATION\fP is generated if \%\f3glPassThrough\fP is executed between
the execution of \%\f3glBegin\fP and the corresponding execution of \%\f3glEnd\fP.
.SH ASSOCIATED GETS
\%\f3glGet\fP with argument \%\f3GL_RENDER_MODE\fP
.SH SEE ALSO
\%\f3glFeedbackBuffer(3G)\fP,
\%\f3glRenderMode(3G)\fP
